This invention relates to woodworking machines, such as a log slabbing chipper. The chipper includes a power-rotated head disposed to one side of a support for a log, and the head supports knife structures on its periphery which operate to chip off wood material on a log with relative movement of the power-driven head with respect to a log thereadjacent. In a chipper as just described, the knife structures on the chipper head are rotated against the side of the log to produce the chipping action. Each knife structure includes one edge portion (a chip cutting edge portion) moving in what might be thought of as a conical path, which functions to cut off chips as the structure is rotated and moved along the side of a log. Each knife structure further includes what is sometimes referred to as a planing edge portion, which moves in a plane and which smoothes or planes a flat surface on the log as the chips are cut off by the chip cutting edge portion.
In a woodworking machine of the type just described, obviously it is important that the knife cutting edge portions be sharp for efficient and accurate cutting of the wood. Additionally, accurate positioning of the knife or knives having the edge portions described is extremely important, if chips of uniform and optimum size are to be obtained.
A general object of the invention is to provide a novel form of knife structure for the rotating head of a woodworking machine, such as a chipper, which includes a pair of knives appropriately mounted to produce a chipping and a planing action as the structure is moved with rotation of the head.
More specifically, an object is to provide a novel knife structure featuring a pair of knives, where each of the knives is a double-edged knife, and the construction enables such a knife to be turned on itself with the replacing after dulling of one edge of the knife with the knife's opposite edge.
Another object is to provide an improved structure for supporting or mounting a knife in a woodworking machine, such as a log slabbing chipper, which enables a knife easily to be turned on itself for the purpose of replacing the edge that is performing the cutting, and further enables the entire knife to be replaced by another knife with minimal or no adjustments required to obtain proper positioning of the knife. With the construction contemplated, knife replacement is rapidly performed.
A further object is to provide novel knife structure for a woodworking machine, such as a log slabbing chipper, which features a pair of double-edged knives disposed end-to-end, and at an angle with respect to each other, with the position of these knives accurately determined. Additionally, the position of the knives is rapidly and accurately reproducible after turning the knives whereby the cutting edges are changed, or after replacing the knives with new knives.
With the construction contemplated, downtime necessitated for the sharpening and repositioning of knives as commonly experienced with prior known construction is sharply reduced.